Cartridge belts are probably as old as firearm cartridges themselves. When firearms progressed from ball, wadding, powder and powder horn to cartridges, undoubtedly the earliest hunters or riflemen secured loops to their belts to allow cartridges to be carried around their waist or over their shoulder as a bandolier. An example of an early, i.e. post Civil War, cartridge belt is illustrated on page 5 of Blue Steel and Gunleather, John E. Bianchi, copyright 1978, Beinfeld Publishing Co., North Hollywood, CA.
Typical of cartridge belts is a design in which a relatively wide belt, e.g. 2 to 3 inches and has a conventional sturdy buckle. Extending around approximately two thirds of the length is a continuous overlying leather strip, narrower in width than the belt and sewn to the belt by vertical stitch lines which form loops between each stitch line.
The belt is selected to match the girth of the wearer, subject to the normal adjustment possible with a buckle and a number of holes. The cartridge loops are designed to hold a particular caliber cartridge snugly with the rim of the casing resting on the top of the cartridge loop and the bullet extending through and sometimes below the loop. Frictional engagement between the casing side wall and the cartridge loop holds the cartridge in place. Finger pressure on the tip of the bullet is sufficient to force the cartridge upward and out of the cartridge loop and into the wearer's hand.
In certain cases, particularly where fabric belts have been used, the cartridge loop is made of elastic material so that the loops may accomodate more than one size cartridge. In no case, to my knowledge, has a cartridge belt been able to accommodiate the full range of cartridge sizes commonly used by shooters of handguns, namely .22 to .458 caliber cartridges.